No abstract

A total of 1290 patients were enrolled in a randomized multicentre double blind study in order to investigate the use of two doses of a new low molecular weight heparin, Logiparin, in the prevention of deep vein thrombosis (DVT) in general surgery. Patients who were included had no contraindication to heparin therapy and had at least one of the recognized risk factors for DVT. Patients were randomized to receive unfractionated heparin (UH) 5000 units b.d., Logiparin 2500 units daily or Logiparin 3500 units daily. Each treatment was given subcutaneously 2 h before surgery and continued for 7-10 days. Daily 125I-labelled fibrinogen uptake tests (FUTs) were performed from day 2 to day 7 to detect DVT, and phleboangiography was used to confirm the diagnosis. The wound was examined on a daily basis to check for haematoma formation, and all patients were followed up for 1 month after operation. All three treatment arms were well matched for age, sex, weight, diagnosis and type of operation performed. The three major inclusion criteria in the trial were malignancy, age over 60 years and a history of varicose veins. Positive FUTs (UH = 4.2 per cent, Logiparin 2500 units daily = 7.9 per cent, Logiparin 3500 units daily = 3.7 per cent) and positive angiograms (UH = 3.0 per cent, Logiparin 2500 units daily = 5.6 per cent, Logiparin 3500 units daily = 2.3 per cent) were significantly more common in the Logiparin 2500 units daily group than in the UH and Logiparin 3500 units daily groups. The rates of major complications (severe haemorrhage, death, pulmonary embolism, reintervention) were similar in the three groups.

In the frame of a multicenter controlled study comparing the efficacy of low-molecular-weight heparin to standard heparin in the prevention of postsurgical thrombosis, 94 phelbograms were centrally evaluated by two independent radiologists. Three months after the first central evaluation, a new reading was performed with the same radiologists, and discrepancies were adjudicated by a senior radiologist. The number of discrepancies between the first and the second evaluation was high: 33 interpretations (35%) had a least one difference, including 14 (14.9%) discrpeancies regarding the main issue, i.e. the presence of venous thrombosis. After the adjudication by the senior radiologist, this number decreased but was still large: 22 films (23.4%) with at least one discrepant item in all and 11 related to the presence of venous thrombosis. This report shows that venous thrombosis assessed by phlebography, which is usually considered as a golden standard in clinical trials, deserves a thorough quality control procedure.